HV transistor structure and corresponding manufacturing method

Abstract

An HV transistor integrated in a semiconductor substrate with a first type of conductivity, comprising a gate region included between corresponding drain and source regions, and being of the type wherein at least said drain region is lightly doped with a second type of conductivity. The drain region comprises a contact region with the second type of conductivity but being more heavily doped, from which a contact pad extends.

What is claimed is:  
     
       1. A high voltage transistor, comprising: 
       a semiconductor substrate of a first conductivity type;  
       a gate region in the substrate;  
       a gate contact pad extending from the gate region;  
       first and second terminal regions on opposite sides of the gate region in the substrate, the first and second terminal regions each including a lightly doped section of a second conductivity type, the first terminal region also including a contact section that is more heavily doped of the second conductivity type than the lightly doped section of the first terminal region; and  
       a first contact pad contacting and extending from the contact section, the contact pad being insulated on opposite sides by respective first and second insulating spacers that are laterally spaced from respective third and fourth insulating spacers positioned on opposite sides of the gate contact pad.  
     
     
       2. The high voltage transistor of claim  1  wherein the second terminal region also includes a contact section that is more heavily doped of the second conductivity type than the lightly doped section of the second terminal region. 
     
     
       3. The high voltage transistor of claim  1  wherein the first contact pad includes a main section formed of a semiconductor material and a connection layer formed of a reaction between the semiconductor material and a metal layer. 
     
     
       4. The high voltage transistor of claim  3  wherein the semiconductor material of the main section of the first contact pad is polysilicon and the connection layer is formed of a silicide. 
     
     
       5. The high voltage transistor of claim  1 , further comprising a second contact pad extending from the second terminal region, the first, second, and gate contact pads all extending to substantially a same height from the substrate. 
     
     
       6. The high voltage transistor of claim  1 , further comprising a gate contact pad extending from the gate region and a second contact pad extending from the second terminal region, each of the contact pads including a silicide layer at an end of the contact pad away from the substrate.